Seismic system for real-time reporting

ABSTRACT

A seismic system for real-time directional reporting for providing radio signals indicating the direction and location of traffic along a path wherein two geophones positioned adjacent said path and spaced from each other are each connected to separate channels each of which includes amplifier means coupled to an integrator capacitor which in turn is coupled to a trigger circuit whereby the signals developed by the geophone are converted to a sharp trigger pulse. The output of each channel is coupled through a diode to a one-shot multivibrator whose output is coupled to a transistor switch in series with the emitter circuit of a transistor audio frequency oscillator and power supply whereby when a trigger pulse from either channel is applied to the one-shot multivibrator the audio frequency oscillator is activated for the period of the one-shot multivibrator. The trigger pulses of the channels are also connected to the inputs of a flip-flop which is set by one channel and reset by the other. The output of the flip-flop is coupled to a transistor switch in series with an astable multivibrator and the power supply whereby said astable multivibrator may be activated when the transistor switch is enabled by the flip-flop.

United States Patent [151 3,699,509

Hirschberg 1 *Oct. 17, 1972 [54] SEISMIC SYSTEM FOR REAL-TIME [57]ABSTRACT REPORTING A seismic system for real-time directional reportinglnventol'l Kelflleth Hirschbel'g, Saratoga, for providing radio signalsindicating the direction and Cam location of traffic along a pathwherein two geophones [73] A i The United states f America as positionedadjacent said path and spaced from each represented by the secretary fthe other are each connected to separate channels each of A whichincludes amplifier means coupled to an integrator capacitor which inturn is coupled to a trigger circuit whereby the signals developed bythe geophone are converted to a sharp trigger pulse. The output of eachchannel is coupled through a diode to a one-shot [22] Filed: Oct. 21,1969 multivibrator whose output is coupled to a transistor switch inseries with the emitter circuit of a transistor [21] Appl 868l42 audiofrequency oscillator and power supply whereby when a trigger pulse fromeither channel is applied to Notice: The portion of the term of thispatent subsequent to Nov. 25, 1986, has been disclaimed.

[ Cl 340/258 340/261 the one-shot multivibrator the audio frequencyoscilla- Cl. tor is activated for the period of the one shot mu]- [58]Fleld of Search ..340/15, 261, 25 D i ib Th t i ul s of the channels arealso connected to the inputs of a flip-flop which is set by [56]References C'ted one channel and reset by the other. The output of theUNITED STATES PATENTS flip-flop is coupled to a transistor switch inseries with an astable multivibrator and the power supply 3,517,3166/l970 Anderson et UM whereby said astable multivibrator may beactivated 3, 1 Dull when the transistor witch is enabled the 3,475,75110/1969 Sontag et al. ..340/26l 3,480,942 11/1969 Hirschberg ..340/l5Primary Examiner-Benjamin A. Borchelt Assistant ExaminerNi Moskowitz 5Claims, 3 Drawing Figures Attorney-Harry M. Saragovitz, Edward J. Kellyand Herbert Berl amp/WI.

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PATENTEDum 17 m2 SHEET 2 [IF 2 ATTOFX'EES SEISMIC SYSTEM FOR REAL-TIMEREPORTING This invention relates to seismic systems for remotemonitoring of roadsand trails in order to determine the volume anddirection of traffic thereon.

Accordingly, an object of the invention is apparatus for detectingmovement of troops or equipment which may occur at either one or twospaced locations along a path and the direction of such movement if itpasses between the spaced'locations.

Another object of the invention is an unmanned transmittingseismicsensor system wherein seismic sensors are positioned at spaced locationsadjacent a path and coupled to unmanned electronic apparatus whichtransmits characteristic identifying radio signals in response to theseismic sensors to remote radio receiver means indicating the locationof persons or equipment moving in the vicinity of the sensor and thedirection of such movement if it passes both spaced sensors.

A still further object of the invention is a seismic system forreal-time reporting utilized in the remote monitoring of roads andtrails in order to determine the volume and direction of trafficthereon.

The invention will be more fully understood from the following detaileddescription taken in connection with the drawings wherein likecharacters identify like ele ments and in which:

FIG. 1a, FIG. 1b and FIG. 1c comprise a schematic diagram of theinvention.

Referring to FIG. 1a, a geophone 10 is placed in contact with the earthadjacent a trail 11 for detection of acoustic waves generated thereindue to troop or equipment movement along the trail in the vicinity ofgeophone 10. A second geophone 12, FIG. lb, is placed in contact withthe earth adjacent trail 11 but remotely located in respect to geophone10 for detection of acoustic waves generated therein due to troop orequipment movement along the trail in the vicinity thereof.

Geophone I is coupled by means of cable 13 to the input ofamplifier-integrator-trigger channel 14, FIG. la, whereby the electricsignals generated by geophone in response to the abovementioned acousticwaves are amplified and subsequently presented as a sharp trigger pulseat the output of channel 14. In a similar manner geophone 12 is coupledby means of cable 13a to amplifier-integrator-pulse channel 15, FIG. lb,which is identical to channel 14 and functions in an identical manner inregard to disturbances along the trail in the vicinity of geophone 12.Since channels 14 and 15 are identical in structure and function, it isto be understood that the following description of channel 14 to beequally applicable to the structure and function of channel 15. I

The seismic signal voltage generated by geophone 10 in response to theaforementioned movement along trail 11 is applied across the resistanceelement of potentiometer 16 by means of cable 13, the rotatable arm ofpotentiometer 16 being coupled to the base electrode of class Aamplifier 0, by means of capacitor 17 whereby said signals are appliedto amplifier Q,. A pair of back to back connected diodes 27 and 28 arecoupled across potentiometer 16 to prevent over-voltage damage toamplifier Q The output of amplifier Q, is directly coupled to emitterfollower 0;, the output of which is capacitively by means of capacitor19 coupled to the input of two stage class A amplifier 18, transistors Qand ()4, for further amplification of the generated seismic signalvoltage. The output of amplifier 18-taken at the collector electrodeoftransistor 0,, is coupled by means of DC. blocking capacitor 22 torectifier diode 24 which rectifies said output to charge integratorcapacitor 23 which is in'series with diode 24 and negative poledconductor or common circuit 21. Diode 29 coupled between the junctionformed by DC. blocking capacitor 22 and rectifier diode 24 and thecommon circuit 21 serves to clamp the output of am plifier 18 aboveground. Voltage divider 25 in shunt with integrator capacitor 23,providing a discharge path for integrator capacitor 23, has anintermediate point coupled through resistor 26 to the base electrode oftransistor 0,, of complementary trigger 34 whereby a percent of theintegrator voltage is applied to and triggers complementary trigger 34resulting in a sharp trigger pulse at the collector electrode oftransistor Q which occurs when the seismic signal is of sufficientstrength and repetition rate. Complementary trigger 34 thus switched onremains in this state and cannot provide another pulse as long asintegrator capacitor 23 remains charged.

Geophone 12 which is in contact with the earth adjacent trail 11 but ata location remote from geophone 10 also developes electrical outputsignals in response to acoustic waves in the earth at this secondlocation due to troop or equipment movement in the vicinity thereof. Theelectrical output signal thus generated by geophone 12 is coupled to theinput of amplifier-integrator-trigger channel 15, identical to channel14, by means of cable 13a and processed in the same manner as describedin conjunction with channel 14 to produce a sharp trigger pulse at theoutput thereof. Thus, as subsequently disclosed, disturbances at eitherlocation may be identified as well as the direction of movement of suchdisturbances between said locations.

A power supply 30, FIG. 1c, is directly coupled across the variouselectronic units of the transmitting seismic sensor system by means ofthe positive poled conductor 20 and negative poled conductor 21 with theexception of astable multivibrator 31, audio frequency oscillator 33,and crystal controlled radio frequency oscillator Q1 each of which haveone power input directly connected to conductor 20 and another powerinput coupled through a transistor switch to conductor 21.

The output pulse of channel 14 taken at the collector of transistor Q iscapactively coupled by means of capacitor 36 to one input of flip-flopmultivibrator 35, transistors Q1 and Q8, FIG. 1c, at the base oftransistor Q and the output pulse of channel 15 taken at the collectorof transistor Q of this channel is coupled by means of capacitor 37 tothe base of transistor 0 whereby the flip-flop 35 is set by the outputof one of said channels and reset by the output of the other of saidchannels. Further description of flip-flop 35 and description ofcircuitry associated therewith in regard to switching audio frequencyoscillator 33 on for a steady tone or off and on whereby a series ofsignals of short duration or beeps are generated is contained in thefollowing. The output pulse of channel 14 is also applied to the inputof a one-shot multivibrator 32,

transistors Q and Q through a diode 38 connected between capacitor 36and the input of one-shot multivibrator 32 and the output pulse ofchannel 15 is similarly applied to the input of one-shot multivibrator32 by means of capacitor 37 and diode 39 whereby the one-shotmultivibrator 32 cycles in response to either or both said pulses forits period of transmission which in one embodiment is 20 seconds. Anaudio frequency oscillator 33, transistor Q has its emitter circuitcoupled to common circuit 21 by means of transistor switch Q Thecollector of switch Q is coupled through emitter resistor 41 to theemitter of transistor Q the emitter thereof is connected to commoncircuit 21 and the base thereof is connected through resistor 40 to theoutput of one-shot multivibrator 32 at the collector of transistor QThus, it can be seen that when pulses from channels 14 or 15 trigger theone-shot multivibrator 32, the subsequent output thereof enablestransistor switch Q which in turn couples audio frequency oscillator 33across power supply 30 for the duration of the period of the one-shotmultivibrator 32 whereupon oscillator 33 generates a continuousuninterrupted audio frequency signal during the time when the astablemultivibrator 31, transistors Q and Q is inactive.

Astable multivibrator 31 is normally inactive during the period thatchannel 15 is activated. A pulse developed by channel 15 is not onlycoupled to the input of one-shot multivibrator 32 but also to the baseof transistor Q of flip-flop 35 driving it into saturation, if it is notalready in this state, whereby transistor switch which is operative tocouple astable multivibrator 31 across power supply 30, is biased off.The common emitter circuit of astable multivibrator 31 is connected tothe collector of transistor switch 0 which has its emitter connected tocommon circuit 21 and the base thereof coupled through means of emitterfollower O to the collector of transistor Q The output of astablemultivibrator 31, taken at the collector of transistor Q is coupled tothe base of emitter follower Q which has its collector connected topositive poled conductor and its emitter in series with the base voltagedivider 42 of transistor Q of audio frequency oscillator 33 whereby saidoscillator 33 is turned off and on at the frequency of astablemultivibrator 31 when activated by the flip-flop 35 through transistorswitch 0, which occurs when a pulse from channel 14 which is applied tothe base of transistor Q causes it to go into saturation whereupon thepotential at the collector of transistor Q rises biasing emitterfollower Q into a conductive state to bias transistor switch Q oncoupling astable multivibrator 31 across power supply and thus enablingit. During the time that astable multivibrator 31 is switched on byaction of transistor switch 0 the collector of transistor Q is switchedback and forth between +12 volts and about half a volt at the rate oftwo times per second and is the output of astable multivibrator 31 thatis applied to the base of emitter follower Q causing the emitter thereofto go alternately between +1 1.5 volts and about half a volt biasingaudio frequency oscillator on and off whereby its output signalcomprises an audio signal switched on and off at the rate of 2 cyclesper second consisting of beeps instead of a steady tone signal as when apulse from channel 15 is coupled to flip-flop and one-shot multivibrator32. Thus, audio frequency oscillator 33 will start either as a steadytone signal or as an interrupted tone signal and will change to theother as the other channel becomes disturbed.

Transistors Q and Q comprise a pulse-shaper and switch, respectively.The audio frequency signal output of audio frequency oscillator 33 istaken at the collector of transistor Q and coupled by means of capacitor42 to the base of transistor 18 through base resistor 43, appearing asan audio frequency pulse at the collector of transistor Q Transistor Qhas its emitter connected to the positive poled conductor 20 and itscollector to the base of transistor switch Q through emitter resistor44. The collector of transistor Q is connected to the common circuit 44of crystal controlled radio frequency oscillator Q and the emitter tocommon circuit 21. The output of radio frequency oscillator Q is coupledto radio frequency amplifier Q for amplification of said output. Anantenna 45 coupled to amplifier Q provides means for radiating theamplified output. When audio frequency oscillator 33 is activated asaforedescribed, the output thereof is coupled by means of capacitor 42to the base of pulseshaper Q resulting in either a steady audiofrequency pulse train, as when channel 15 is activated, or a series ofaudio frequency pulse trains, as when channel 14 is activated, at thecollector thereof which are coupled to the base of transistor switch 0which is thereby enabled. Transistor switch 0 in response to said audiofrequency pulses connects radio frequency oscillator Q across powersupply 30 whereby it is activated and applies the steady tone audiofrequency pulse or a series beeps, of audio frequency pulses to radiofrequency oscillator Q20 causing pulse modulation thereof. The pulsemodulated output of oscillator Q20 is amplified by amplifier Q theoutput of which is radiated by antenna 45. Thus, from the foregoing, itcan be seen that the crystal controlled radio frequency oscillator 0 caneither be switched on and pulse modulated to produce a steady audio tonepulse modulated radio signal having the duration of one-shotmultivibrator 32 or off and on at the rate of 2 cycles per second, thefrequency of astable multivibrator 31, and pulse modulated to produce aseries of audio tone pulse modulated radio signals indicating whichchannel has been activated and thereby the location of the disturbanceas well as the direction of travel of such disturbance as the otherchannel becomes activated. These audio tone pulse modulated radiosignals are received by radio receiving stations remotely located withreference to the location of the aforedescribed apparatus.

What is claimed is:

1. A transmitting seismic sensor system for real-time directionalreporting for the purpose of both transmitting and converting intorecognizable form information from geophones spaced along a path inresponse to acoustic waves in the earth generated therein by trafficflow on the path pass the geophones whereby the direction and volume ofthe traffic can be determined comprising, in combination: a DC. powersupply coupled to said system for energizing said system; a firstgeophone positioned adjacent said path on the surface of the earth todetect acoustic waves transmitted therethrough due to traffic on saidpath; a first electronic channel coupled to said first geophone forproducing amplified seismic signals and converting the amplified seismicsignals to a trigger pulse at the output thereof; a second geophonepositioned adjacent said path on the surface of the earth remote fromsaid first geophones to detect acoustic waves transmitted therethroughdue to said traffic as it passes thereby; a second electronic channelcoupled to said second geophone for producing amplified seismic signalsand converting the amplified seismic signals to a trigger pulse at theoutput thereof; a transistor audio frequency oscillator adapted toproduce a steady or interrupted output signal having the emitter circuitthereof coupled to the common circuit of said system through the outputof a first electronic switching device and the input biasing meansthereof coupled across the D.C. power supply through an emitterfollower; a one-shot multivibrator having the input thereof capacitivelycoupled through diode means to the output of said electronic channelsand the output thereof coupled to the input of said first electronicswitching device whereby when either said channel triggers the one-shotmultivibrator it cycles to enable said first electronic switching devicewhereby the transistor audio frequency oscillator is activated; anastable multivibrator having the output thereof coupled to the input ofsaid emitter follower and the common circuit thereof coupled through theoutput of a second electronic switching device to the common circuit ofsaid system; a bistable multivibrator provided with a first inputcoupled to the output of said first channel and a second input coupledto the output of said second channel and an output coupled to the inputof said second electronic switching device whereby when a trigger pulsefrom said first channel is applied to said first input said secondelectronic switching device is enabled coupling the astablemultivibrator across the power supply whereby it generates biasingsignals which are applied through the emitter follower to said inputbiasing means to bias said audio frequency oscillator on and off at thefrequency of the astable multivibrator to produce an interrupted audiofrequency tone signal output, and whereby when a trigger pulse from saidsecond channel is applied to said second input the second electronicswitching device is disabled and the audio frequency oscillator producesa steady audio frequency tone signal output; a transistor pulse shapercoupled to the output of the audio frequency oscillator whereby theoutput of the audio frequency oscillator is converted to pulse tonesignals; a radio frequency transmitter having an antenna coupledthereto; a third electronic switching device having an input coupled toand responsive to said pulse tone signals to enable the output thereofcoupled between said power supply and said radio frequency transmittersignals at the out ut thereof; a pair of diodes connected in oppositecon uctmg directions to each other across input of said class Aamplifier forpreventing excessive voltage from the geophone beingapplied thereto; a multistage transistor class A amplifier for furtheramplifying the amplified seismic signals; an emitter follower couplingsaid class A amplifier and said multistage class A amplifier; anintegrator capacitor provided with a voltage divider in paralleltherewith and having one terminal coupled to the common circuit of saidsystem; a rectifier coupled in series with another terminal of theintegrator capacitor and the output of said multistage class A amplifierwhereby the further amplified seismic signals are rectified and chargethe integrator capacitor; and a complementary transistor trigger havingthe input thereof coupled to an intermediate point on said voltagedivider and responsive to a portion of the voltage developed across saiddivider due to charging of the integrator capacitor to produce saidtrigger pulse.

3. The invention in accordance with claim 2 wherein said firstelectronic switching device comprises a transistor having base, emitterand collector elements, said base element connected to the output of theoneshot multivibrator, said emitter element connected to the emittercircuit of the audio frequency oscillator, and said emitter elementconnected to the common circuit of said system.

4. The invention in accordance with claim 3 wherein said secondelectronic switching device comprises a transistor having base, emitterand collector elements, said base element coupled through an emitterfollower to the output of the bistable multivibrator, said collectorelement connected to the common circuit of the astable multivibrator andsaid emitter element connected to the common circuit of said system.

5. The invention in accordance with claim 4 wherein said thirdelectronic switching device comprises a transistor having base, emitterand collector element, said base element coupled to the output of saidtransistor pulse shaper, said collector element coupled to the commoncircuit of said radio frequency transmitter, and said emitter elementcoupled to the common circuit of said system.

1. A transmitting seismic sensor system for real-time directionalreporting for the purpose of both transmitting and converting intorecognizable form information from geophones spaced along a path inresponse to acoustic waves in the earth generated therein by trafficflow on the path pass the geophones whereby the direction and volume ofthe traffic can be determined comprising, in combination: a D.C. powersupply coupled to said system for energizing said system; a firstgeophone positioned adjacent said path on the surface of the earth todetect acoustic waves transmitted therethrough due to traffic on saidpath; a first electronic channel coupled to said first geophone forproducing amplified seismic signals and converting the amplified seismicsignals to a trigger pulse at the output thereof; a second geophonepositioned adjacent said path on the surface of the earth remote fromsaid first geophones to detect acoustic waves transmitted therethroughdue to said traffic as it passes thereby; a second electronic channelcoupled to said second geophone for producing amplified seismic signalsand converting the amplified seismic signals to a trigger pulse at theoutput thereof; a transistor audio frequency oscillator adapted toproduce a steady or interrupted output signal having the emitter circuitthereof coupled to the common circuit of said system through the outputof a first electronic switching device and the input biasing meansthereof coupled across the D.C. power supply through an emitterfollower; a one-shot multivibrator having the input thereof capacitivelycoupled through diode means to the output of said electronic channelsand the output thereof coupled to the input of said first electronicswitching device whereby when either said channel triggers the one-shotmultivibrator it cycles to enable said first electronic switching devicewhereby the transistor audio frequency oscillator is activated; anastable multivibrator having the output thereof coupled to the input ofsaid emitter follower and the common circuit thereof coupled through theoutput of a second electronic switching device to the common circuit ofsaid system; a bistable multivibrator provided with a first inputcoupled to the output of said first channel and a second input coupledto the output of said second channel and an output coupled to the inputof said second electronic switching device whereby when a trigger pulsefrom said first channel is applied to said first input said secondelectronic switching device is enabled coupling the astablemultivibrator across the power supply whereby it generates biasingsignals which are applied through the emitter follower to said inputbiasing means to bias said audio frequency oscillator on and off at thefrequency of the astable multivibrator to produce an interrupted audiofrequency tone signal output, and whereby when a trigger pulse from saidsecond channel is applied to said second input the second electronicswitching device is disabled and the audio frequency oscillator producesa steady audio frequency tone signal output; a transistor pulse shapercoupled to the output of the audio frequency oscillator whereby theoutput of the audio frequency oscillator is converted to pulse tonesignals; a radio frequency transmitter having an antenna coupledthereto; a third electronic switching device having an input coupled toand responsive to said pulse tone signals to enable the output thereofcoupled between said power supply and said radio frequency transmitterwhereby the radio frequency transmitter is coupled across the powersupply and the pulse tone signals are applied to and pulse modulate saidtransmitter to provide identifying pulse modulated radio frequencysignals indicative of the direction of travel of said traffic.
 2. Theinvention in accordance with claim 1 wherein said first and secondelectronic channels each comprise in combination: a transistor class Aamplifier coupled to said geophone for producing amplified seismicsignals at the output thereof; a pair of diodes connected in oppositeconducting directions to each other across the input of said class Aamplifier for preventing excessive voltage from the geophone beingapplied thereto; a multistage transistor class A amplifier for furtheramplifying the amplified seismic signals; an emitter follower couplingsaid class A amplifier and said multistage class A amplifier; anintegrator capacitor provided with a voltage divider in paralleltherewith and having one terminal coupled to the common circuit of saidsystem; a rectifier coupled in series with another terminal of theintegrator capacitoR and the output of said multistage class A amplifierwhereby the further amplified seismic signals are rectified and chargethe integrator capacitor; and a complementary transistor trigger havingthe input thereof coupled to an intermediate point on said voltagedivider and responsive to a portion of the voltage developed across saiddivider due to charging of the integrator capacitor to produce saidtrigger pulse.
 3. The invention in accordance with claim 2 wherein saidfirst electronic switching device comprises a transistor having base,emitter and collector elements, said base element connected to theoutput of the one-shot multivibrator, said emitter element connected tothe emitter circuit of the audio frequency oscillator, and said emitterelement connected to the common circuit of said system.
 4. The inventionin accordance with claim 3 wherein said second electronic switchingdevice comprises a transistor having base, emitter and collectorelements, said base element coupled through an emitter follower to theoutput of the bistable multivibrator, said collector element connectedto the common circuit of the astable multivibrator and said emitterelement connected to the common circuit of said system.
 5. The inventionin accordance with claim 4 wherein said third electronic switchingdevice comprises a transistor having base, emitter and collectorelement, said base element coupled to the output of said transistorpulse shaper, said collector element coupled to the common circuit ofsaid radio frequency transmitter, and said emitter element coupled tothe common circuit of said system.